Ladders, scaffolds and other similar structures have been in use for many years. In general, ladders fit into two categories--they are either straight ladders or A-frame ladders. In both types, the feet of the ladders are set on the ground or at the lowest practical level with the top section resting against the top of the structure to be climbed, as would apply to a straight ladder; or with the top near the structure as would be the case with the A-frame.
The scaffolds and similar structures in current use are attached to the side of a stationary structure by either permanent or temporary means and in some types, supplementary implements are included that allow the scaffold to be raised or lowered as required.
A search of the prior art did not disclose any ladders or scaffold structures that were designed to be attached or hooked to a set of attachment hooks that are permanently set into a stationary structure such as a wall or frame. Additionally, scaffolds or ladders that can be collapsed to a relatively flat surface, when in their hooked position, and/or not in use, were not found in the prior art. Although the search did not uncover any patents that read directly on the claims of the instant invention, the following U.S. patents are considered related and indicative of the state-of-the-art.
______________________________________ U.S. PAT. NO. INVENTOR ISSUED ______________________________________ 3,552,522 Bobo 5 June 1971 3,231,043 Brown 25 January 1966 3,158,225 Almgren 24 November 1964 2,279,850 Vansickle 14 April 1942 ______________________________________
The Bobo patent discloses a portable scaffold having an elongated, horizontal support that can be detachably connected to the side of a building. The scaffold includes a lateral support projecting from the horizontal support that is used to support a load such as workmen. The outer end of the lateral support is connected to an upstanding member while the inward end is supported by a stationary support.
The Brown patent discloses a portable scaffold structure for use on windows and other openings in a building. The scaffold includes a pair of elongated suspension members that have a hooked upper section designed to be hung over the ledge or sill of an open window. The lower section extents outwardly to form a support ledge on which is set an elongated, flat platform that is used to support a load.
The Almgren patent discloses a scaffold bracket that is primarily designed for concrete wall forms and that can be dismanteled after use. The bracket includes a vertical member having on its upper and lower back side an inverted U-flange. The U-flanges are sized to extend over a building wall. In the outer end of the upper U-flange is attached a horizontal workman support structure that is held in place on its inward side by a channel attached to the top of the U-flange and on its outward side by a vertical member. The lower end of the vertical member is attached to the outer end of the lower U-flange.
The Vansickle patent discloses a scaffold support adaptable for mounting on various types of wall structures. The scaffold consists of an angular bracket having a set of connecting legs which extend at right angles to each other. Extending between the connecting legs is a triangular brace. Projecting from the legs are a plurality of spurs or prongs for retaining the scaffold planking on the bracket. The legs of the bracket also includes in its inner portion a series of keyhole slots. Selectively engageable in the slots is the angularly extending end portion of a securing rod that is held by a retaining nut.